This invention relates to an organic electroluminescence device (hereinafter occasionally called as an organic EL device) and its manufacturing method thereof.
Conventionally, various sealing methods and moisture protecting methods for an electro-luminescence element and an electro-luminescence apparatus comprising an electro-luminescence device and a florescent medium with a combination have been investigated to prevent the bad effect of water in the atmosphere and not to produce the non-emission parts or non-emission spots, which may be sometimes referred to dark spots.
For example, the organic EL device having a sealing means which covers an organic EL element and a drying agent is disclosed in JP-A-9-148066. Also, the organic EL device having a protective layer made from inorganic materials such as Germanium oxide (GeO) onto the upper electrode for protecting the moisture is disclosed in JP-A-7-14675.
However, with a progress of a high resolution organic EL device and organic EL element, non-emission parts or non-emission spots which width or diameter is several 10 micrometers, are produced around the pixel as shown in FIG. 15, and there is the problem that the brightness decreases as the emitting area shrinks.
In the organic light-emission medium formed by using an ink-jet printing method according to JP-A-11-40358 and JP-A-11-54270, and the organic light-emission medium formed by using a micelle disruption method according to JP-A-11-87054, many non-emission parts or non-emission spots are remarkably produced with a comparison of the organic light-emission medium formed by using a deposition method. Also, it is difficult to prevent efficiently the production of the non-emission parts or non-emission spots by the conventional sealing means or the moisture proofing techniques.
So that, the present inventors have studied the prior arts problems, have found that the water contained in both of the planarizing layer and the intermediate insulating layer migrates to the organic light-emission medium or the upper electrode and gives much worse effect of the oxidation of them than the water which invades from the outside as theoretically shown in FIGS. 16 and 17, and have proposed the organic EL device having the good durability by improving such water problems.
For example, the organic EL device having a planarizing layer which water content is 1.0 wt. % or less between a florescent medium and a lower electrode is proposed in JP-A-11-26156. Also, the organic EL device having an intermediate insulating layer comprising a drying agent inside to keep the water content of 0.1 wt. % or less is proposed in JP-A-11-54285.
However, in the organic EL devices according to JP-A-11-26156 and JP-A-11-54285, although it is possible to prevent the production of non-emission area or non-emission part in some extent during the storing at the room condition, but it is difficult to prevent the production of non-emission area or non-emission part and the shrinkage of the emitting area during the storing at the high-temperature condition such as 80xc2x0 C., and to obtain the high brightness for a long time.
Thus, the inventors have keen studied these problems and have found that there is the critical relationship between the water content of the organic light-emission medium after fabricating the organic EL device and the production of non-emission area or non-emission part and the shrinkage of the emitting area and such production of non-emission area or non-emission part around the pixels are remarkably prevented by keeping the water content below the predetermined value.
The object of the present invention is to provide the organic EL device which can prevent the production of non-emission area or non-emission part, even if the pixel area becomes high resolution (for example, size of 100 xcexcmxc3x97300 xcexcm square), the organic light-emission medium is formed by the wetting process (for example, coating process) or it is stored for a long time at the high-temperature condition (for example, 80xc2x0 C., 2 weeks).
Thus, it is the object to provide the organic EL device having the good heat resistance and the long life brightness property and its manufacturing method thereof.
One embodiment of the present invention is an organic EL device comprising a lower electrode, an organic light-emission medium and an upper electrode (opposite electrode) on a support substrate, wherein a water content of the organic light-emission medium is 0.05 wt. % or less. Thus, the above-mentioned problems can be solved.
Namely, by constituting the organic EL device like this, it is possible to prevent the oxidation of the upper electrode (opposite electrode) based on the water that is included in a light-emission medium. Thus, the shrinkage of the light-emission area and the decrease of the luminescence brightness can be prevented for a long time at the high temperature condition as well as the room condition.
Another embodiment of the present invention is an organic EL device comprising a lower electrode, an intermediate insulating layer (sometimes called as an electrically insulating layer), an organic light-emission medium and an upper electrode (opposite electrode) on a support substrate, wherein a water content of the intermediate insulating layer and the organic light-emission medium is 0.05 wt. % or less.
By constituting the organic EL device like this, it is possible to provide the fine pitch matrix of the electrodes since the good electrically insulation between the lower electrode and the upper electrode are obtained. In addition, the shrinkage of the light-emission area and the decrease of the luminescence brightness can be prevented for a long time at the high temperature condition such as 80xc2x0 C. as well as the room condition.
Note that, as a modification of the above-described organic EL device, it is also favorable to provide both or each of a color filter and a florescence medium on the opposite side of the upper electrode (opposite electrode) having a light-emission medium, a planarizing layer, or a sealing member and the like.
A further embodiment of the present invention is an organic EL device comprising each or both of a color filter and a florescence medium, a lower electrode, an intermediate insulating layer, an organic light-emission medium and an upper electrode (opposite electrode) on a support substrate, wherein a water content of the each or both of the color filter and the florescence medium, the intermediate insulating layer and the organic light-emission medium is 0.05 wt. % or less.
By constituting the organic EL device like this, a multi-color display may be easily obtained and the shrinkage of the light-emission area based on the production of non-emission area or non-emission part can be prevented for a long time at the high temperature condition such as 80xc2x0 C.
A further embodiment of the present invention is an organic EL device comprising the each or both of a color filter and a florescence medium, a planarizing layer, a lower electrode, an intermediate insulating layer, an organic light-emission medium and an upper electrode (opposite electrode) on a support substrate, wherein a water content of the each or both of the color filter and the florescence medium, the planarizing layer, the intermediate insulating layer and the organic light-emission medium and is 0.05 wt. % or less.
By constituting the organic EL device like this, a multi-color display may be easily obtained and the preventing of the short-circuiting based on the roughness of a florescence medium and the like becomes easy. In addition, the shrinkage of the light-emission area based on the production of non-emission area or non-emission part can be prevented for a long time at the high temperature condition such as 80xc2x0 C.
further embodiment of the present invention is a method for manufacturing an organic EL device comprising a lower electrode, an organic light-emission medium and an upper electrode (opposite electrode) on a support substrate, wherein
a drying step is carried out before and after forming of the organic light-emission medium or each occasion in order to keep that a water content of the organic light-emission medium after fabricating the organic EL device is 0.05 wt. % or less.
By carrying out the method like this, it is possible efficiently to provide an organic EL device which can prevent the shrinkage of the light-emission area based on the production of non-emission area or non-emission part for a long time at the high temperature condition such as 80xc2x0 C.
In a method for manufacturing an organic EL device according to the present invention, it is favorable that the dew point at the drying step is maintained at xe2x88x9210xc2x0 C. or less.
By carrying out the method like this, it is possible to dry the water in a short time by using a simple apparatus.
In a method for manufacturing an organic EL device according to the present invention, it is favorable that the evacuated pressure at the drying step is 13.3 Pa (0.1 Torr) or less.
By carrying out the method like this, it is possible to dry the water in a short time by using a simple apparatus.
In a method for manufacturing an organic EL device according to the present invention, it is favorable that the heating temperature at the drying step is from 60 to 300xc2x0 C.
By carrying out the method like this, it is possible to dry the water in a short time by using a simple apparatus.
In a method for manufacturing an organic EL device according to the present invention, it is favorable that an inert gas is used at the drying step.
By carrying out the method like this, it is possible to dry the water in a short time without oxidizing a light-emission medium and electrodes.
A further embodiment of the present invention is a method for manufacturing an organic EL device wherein an apparatus comprising a drying unit, a deposition unit and a conveying unit between these units is used,
the drying step for a substrate is carried out before and after forming of the organic light-emission medium or each occasion in the drying unit, the conveying step of the substrate to the deposition unit is carried out by using a conveyer in the conveying unit, and the forming step of an organic light-emission medium is carried out in the deposition unit.
By carrying out the method like this, it is possible to dry the water efficiently in a light-emission medium after fabricating the organic EL device.
A further embodiment of the present invention is a method for manufacturing an organic EL device wherein an electroluminescence element comprising a lower electrode, an organic light-emission medium and an upper electrode on a support substrate, and sealing parts having each or both of a color filter and fluorescence medium on a sealing substrate are laminated, wherein
a drying step is carried out for at least the organic light-emission medium and the sealing parts in order to keep that a water content of the organic light-emission medium after fabricating the organic EL device is 0.05 wt. % or less.
By carrying out the method like this, it is possible to provide an organic EL device having a color display efficiently. In addition, it is possible to provide the organic EL device that can prevent the shrinkage of the light-emission area based on the production of non-emission area or non-emission part for a long time, even if a fluorescence medium is formed on the side of a sealing substrate.
A further embodiment of the present invention is a method for manufacturing an organic EL device comprising a lower electrode, an organic light-emission medium and an upper electrode (opposite electrode) on a support substrate, wherein
a drying step is carried out after forming of the organic light-emission medium by using a wetting process in order to keep that a water content of the organic light-emission medium after fabricating the organic EL device is 0.05 wt. % or less.
By carrying out the method like this, it is possible to provide the organic EL device, which can prevent the shrinkage of the light-emission area based on the production of non-emission area or non-emission part for a long time without oxidizing a light-emission medium and an opposite electrode, even if using a wetting process forms a light-emission medium.
A further embodiment of the present invention is a method for manufacturing an organic EL device, wherein an apparatus comprising a drying unit, a deposition unit and a conveying unit between these units is used, the organic light-emission medium is formed by using a wetting process,
the drying step for a substrate is carried out after a formation of the organic light-emission medium in the drying unit,
the conveying step of the substrate to the deposition unit is carried out by using a conveyer in the conveying unit, and
the forming step of an upper electrode is carried out in the deposition unit.
By carrying out the method like this, it is possible to efficiently dry the water in a light-emission medium after fabricating the organic EL device.